Everyone, it seems, is talking about Caster Semenya, the 18-year-old South African who has had to submit to gender verification tests after posting some excellent 800m times this summer, among them last night's gold medal-winning 1 minute 55 seconds in Berlin. Unfortunately not everyone has mustered the sensitivity such topics demand: the Sun's "800m and two veg" headline is crass; the announcement by the International Association of Athletics Federations (IAAF) a matter of hours before yesterday's final was rather more surprisingly tactless.

The tests were requested at the end of July, after Semenya's impressive showing at the African junior championships in Mauritius but, given the complex nature of gender differentiation, the results are still some weeks away. Why, when those who test positively for drugs are often protected from media attention until months after competitions, did the IAAF opt to reveal the altogether more personal testing undergone by Semenya before the results were even known? And when she still had to walk out at the Olympic stadium and compete in the final? The timing suggests it needed to be seen to be doing something in response to stage whispers about Semenya's physique, and opted to save its own face rather than protect a young athlete from the unwanted attention of the world's media.

Wholesale gender testing of female athletes was introduced at European and then Olympic level in the 1960s, but suspended in the late 1990s. Although the tests evolved from a humiliating parade in front of a panel of doctors to more sophisticated DNA testing in that time, the accuracy of results was continually questioned by scientists. Frighteningly, the Confederation of African Football will implement gender testing ahead of next year's African Women's Championship. Their definition of a woman? Someone who is menstruating. Besides such obviously problematic classifications, a genetic condition like androgen insensitivity syndrome (AIS) means that a physiological woman can have male chromosomes – and not to any athletic advantage. More importantly, women with such a condition could be completely unaware of it, as was Indian 800m runner Santhi Soundarajan, who was stripped of her silver medal and reported to have attempted suicide in the wake of her very public gender test "failure" due to AIS at the 2006 Asian games. If Semenya's results were to indicate something like AIS, she would have to deal with the psychological impact in the full glare of the media spotlight.

To her credit, Semenya has so far handled the situation with good grace, though this evening's medals ceremony will be another test of her composure. Britain's Jenny Meadows, who will collect bronze, has remained diplomatic when questioned, but one or two athletes who finished outside of the medal places have disputed Semenya's sex in rather blunt terms. Elisa Cusma, the Italian who finished in sixth, told reporters: "She's a man." No one will know precisely Semenya's biological sex until the test results are confirmed, when we will all know.

Cusma's certainty is alarming not only because it is so far unfounded and so publicly denigrates a fellow competitor, but also because it relies upon a gender binary that is nothing more than a comforting illusion. The fact that "She looks like a man", or "He acts like a girl", tells us as much. It has long suited us to organise the world into "men" and "women", and cast those "in between" as abnormalities, particularly when competitions are organised around the division of athletes into these two categories. To do things differently would take a complete rethink and no doubt produce some equally insufficient boundaries. But certainly our preparedness to rely on surface clues and use them to pose personal questions, in such a public manner and to athletes so young and inexperienced, should be pause for thought.